vapour pressure of a deliquescent substance is less than that of the water vapour in air because these substances absorb water vapor and thus reduce its vapor pressure. Please look at the below table
Systematic name Water vapor
Liquid State water
Solid state ice
Properties[1]
Molecular formula H2O
Molar mass 18.01528(33) g/mol
Melting point 0 °C (273 K)[2]
Boiling point 99.98 °C (373.13 K)[2]
specific gas constant 461.5 J/(kg·K)
Heat of vaporization 2.27 MJ/kg
specific heat capacity
at constant pressure 1.84 kJ/(kg·K)